xref: /src/doc/HACKS

# $NetBSD: HACKS,v 1.116 2011/08/15 02:29:38 mrg Exp $
#
# This file is intended to document workarounds for currently unsolved
# (mostly) compiler bugs.
#
# Format:
#   hack		title
#   cdate		creation date
#   mdate		mod date
#   who			responsible developer
#   port		...
#  	  affected ports, space separated, if not "all"
#   file		affected file : revision : line from : line to
#  	  affected files and revision and line numbers describing hack
#  	  multiple lines if necessary.
#   pr			NNNN ...
#  	  problem reports this hack works around, if known. Space
#  	  separated.
#   regress		src/regress/directory/where/test/found
#  	  regression test directories, if available.
#   descr
#  	  insert short informal description (multi-line). (Longer ones
#  	  should be in the PR database. More formal descriptions might
#  	  be in the regress tree. See above).
#   kcah
#  	  closing bracket.
#
# this is a comment.

hack	netstat ieee1394 address printing.
mdate	14 Nov 2000
who	matt
file	lib/libc/net/getnameinfo.c	: 1.32 : 497 : 503
descr
	Because the current implementation of IP over IEEE1394, the
	fw device address contains more than just the IEEE1394 EUI-64.
	So when printing out IEEE1394 addresses, ignore the extra stuff.
kcah

hack	xterm vs. libterm
mdate	01 Aug 2000
who	jdc
file	xsrc/xc/programs/xterm/main.c	: 1.2 : 3609 : 3614
pr	10383
descr
	In order to extend the termcap string over 1023 bytes, a ZZ entry was
	introduced to point to a memory location containing the full entry.
	Without this hack, xterm will export a termcap containing the ZZ
	entry, which will then be ignored by libterm.  As xterm modifies the
	exported termcap, this would cause those modifications to be ignored.
kcah

hack	wi-at-big-endian-bus
cdate	15 Mar 2002
who	martin
file	dev/ic/wireg.h
descr	Add an option to access the underlying bus in big endian byte order
	to work around deficiencies in bus_space_{read,write}_* macros.
	Those don't allow the implementation of a proper pcmcia bus space
	tag.
kcah

hack	specific knowledge of colours in curses code
cdate	Sun Apr  6 11:05:24 BST 2003
who	jdc
file	lib/libcurses/color.c : r1.24
descr
	Swap red/blue and yellow/cyan colours for COLOR_OTHER.
	Fix is to enhance libtermcap to understand terminfo-style % sequences.
	See also:
	    http://mail-index.NetBSD.org/tech-userlevel/2003/04/06/0000.html
kcah

hack	Compensation for differing types of LINUX_USRSTACK and USRSTACK
cdate	21 Aug 2003
who	he
file	sys/miscfs/procfs/procfs_linux.c : 1.14
descr
	Not all ports have LINUX_USRSTACK and/or USRSTACK defined as
	literals/constants, but refer to variables of a type which is
	not "unsigned long", causing compilation of procfs_linux.c to
	fail with "makes integer from pointer without a cast".  This
	is observed on e.g. the sun3 port.  Ideally the "types" for
	symbols should be consistent across all ports.
kcah

hack	gcc-strict-aliasing
cdate	6 August 2004
who	junyoung
pr	26516
file	src/usr.sbin/racoon/racoon/Makefile : 1.21
descr
	GCC issues a warning "dereferencing type-punned pointer will break
	strict-aliasing rules" when compiling
	crypto/dist/kame/racoon/crypto/openssl.c with -O[23s]. Note that this
	is due to use of type casting in a non-standard way in the code and
	not a compiler bug. Once a new release of KAME with a proper fix
	applied is imported this should be backed out.
kcah

hack	gcc4 wrong uninitialized variable
mdate	10 May 2006
who	mrg
file	bin/ksh/eval.c			: 1.6
file	bin/sh/histedit.c		: 1.39
file	bin/sh/parser.c			: 1.60
file	crypto/dist/heimdal/kdc/524.c	: 1.10
file	crypto/dist/ssh/sftp.c		: 1.20
file	crypto/dist/ssh/ssh-keysign.c	: 1.11
file	dist/ipf/lib/hostname.c		: 1.2
file	dist/ipf/tools/ipmon.c		: 1.8
file	dist/ntp/ntpd/ntp_request.c	: 1.4
file	dist/ntp/ntpd/refclock_shm.c	: 1.4
file	dist/ntp/sntp/timing.c		: 1.3
file	dist/pppd/pppstats/pppstats.c	: 1.3
file	dist/smbfs/lib/smb/rap.c	: 1.6
file	dist/tcpdump/print-zephyr.c	: 1.5
file	distrib/utils/sysinst/aout2elf.c : 1.12
file	gnu/libexec/uucp/uucico/uucico.c : 1.6
file	lib/libc/citrus/citrus_csmapper.c : 1.6
file	lib/libc/citrus/citrus_pivot_factory.c : 1.5
file	lib/libc/inet/inet_cidr_ntop.c	: 1.3
file	lib/libc/inet/inet_ntop.c	: 1.3
file	lib/libc/stdio/vfwprintf.c	: 1.8
file	libexec/ld.elf_so/arch/m68k/mdreloc.c : 1.20
file	libexec/ld.elf_so/arch/powerpc/ppc_reloc.c : 1.40
file	libexec/ld.elf_so/arch/sh3/mdreloc.c : 1.22
file	libexec/ld.elf_so/arch/sparc/mdreloc.c : 1.39
file	libexec/ld.elf_so/arch/sparc64/mdreloc.c : 1.39
file	libexec/ld.elf_so/arch/vax/mdreloc.c	: 1.21
file	libexec/ld.elf_so/arch/x86_64/mdreloc.c	: 1.27
file	sbin/fsck_ext2fs/dir.c		: 1.19
file	sbin/routed/rtquery/rtquery.c	: 1.18
file	sys/arch/amd64/amd64/pmap.c	: 1.26
file	sys/arch/i386/pci/piixpcib.c	: 1.4
file	sys/arch/m68k/m68k/pmap_motorola.c	: 1.4
file	sys/crypto/cast128/cast128.c	: 1.9
file	sys/ddb/db_command.c		: 1.86
file	sys/dev/cardbus/cardbus_map.c	: 1.21
file	sys/dev/fss.c			: 1.25
file	sys/dev/ic/igsfb.c		: 1.39
file	sys/dev/ic/mb86950.c		: 1.5
file	sys/dev/ic/midway.c		: 1.71
file	sys/dev/kttcp.c			: 1.18
file	sys/dev/rasops/rasops_bitops.h	: 1.9
file	sys/dev/pci/cmpci.c		: 1.31
file	sys/dev/pci/machfb.c		: 1.45
file	sys/dev/usb/ohci.c		: 1.174
file	sys/dev/usb/uhci.c		: 1.196
file	sys/dev/rasops/rasops_bitops.h	: 1.9
file	sys/dist/ipf/netinet/ip_nat.c	: 1.10
file	sys/dist/ipf/netinet/ip_rpcb_pxy.c : 1.8
file	sys/dist/pf/net/pf.c		: 1.22
file	sys/fs/udf/udf_vnops.c		: 1.4
file	sys/kern/kern_sig.c		: 1.219
file	sys/kern/tty.c			: 1.181
file	sys/net/bpf.c			: 1.116
file	sys/net/zlib.c			: 1.26
file	sys/netccitt/if_x25subr.c	: 1.37
file	sys/netinet/in.c		: 1.107
file	sys/netsmb/smb_smb.c		: 1.27
file	sys/netsmb/smb_trantcp.c	: 1.22
file	sys/nfs/nfs_serv.c		: 1.108
file	sys/nfs/nfs_socket.c		: 1.129
file	sys/nfs/nfs_syscalls.c		: 1.91
file	sys/ufs/lfs/lfs_vfsops.c	: 1.207 [also (char *)]
file	usr.bin/ftp/ftp.c		: 1.140
file	usr.bin/find/function.c		: 1.54
file	usr.bin/mail/tty.c		: 1.20
file	usr.bin/msgc/msg_sys.def	: 1.33-1.34
file	usr.bin/nl/nl.c			: 1.7
file	usr.bin/systat/keyboard.c	: 1.23
file	usr.bin/usbhidctl/usbhid.c	: 1.29
file	usr.bin/vi/cl/cl_read.c		: 1.5
file	usr.bin/vi/ex/ex_cscope.c	: 1.12
file	usr.bin/vi/ex/ex_tag.c		: 1.19
file	usr.bin/vi/vi/v_txt.c		: 1.15
file	usr.sbin/altq/altqstat/qdisc_rio.c : 1.4
file	usr.sbin/cron/do_command.c	: 1.19
file	usr.sbin/timed/timed/slave.c	: 1.15
descr
	GCC 4.1 gets many uninitialised variable warnings wrong.  We should
	really audit all the old hacks like this when older compilers are
	removed from the tree, as many are probably no longer required.
	The problem is that it does not recognize initialization via function
	call pointer. I.e.
		int p;
		foo(&p);
	does not mark p as initialized.
kcah

hack	gcc4 pointer sign and strict aliasing problems
mdate	10 May 2006
who	mrg
file	bin/ed/Makefile			: 1.33
file	distrib/utils/sysinst/Makefile.inc : 1.44
file	distrib/utils/x_dhclient/Makefile : 1.15
file	games/bcd/Makefile		: 1.5
file	games/dab/Makefile		: 1.5
file	games/larn/Makefile		: 1.17
file	games/pom/Makefile		: 1.5
file	lib/libasn1/Makefile		: 1.26
file	lib/libcrypt/Makefile		: 1.17
file	lib/libgssapi/Makefile		: 1.16
file	lib/libhdb/Makefile		: 1.20
file	lib/libkadm5clnt/Makefile	: 1.21
file	lib/libkadm5srv/Makefile	: 1.25
file	lib/libkrb5/Makefile		: 1.35
file	lib/libssh/Makefile		: 1.6
file	lib/libtelnet/Makefile		: 1.26
file	libexec/getty/Makefile		: 1.14
file	libexec/kadmind/Makefile	: 1.19
file	libexec/kpasswdd/Makefile	: 1.14
file	sbin/atactl/Makefile		: 1.3
file	sbin/cgdconfig/Makefile		: 1.7
file	sbin/clri/Makefile		: 1.13
file	sbin/dkctl/Makefile		: 1.4
file	sbin/dump/Makefile		: 1.33
file	sbin/fdisk/Makefile		: 1.35
file	sbin/fsck_ext2fs/Makefile	: 1.11
file	sbin/fsck_ffs/Makefile		: 1.29
file	sbin/fsdb/Makefile		: 1.18
file	sbin/mount_smbfs/Makefile	: 1.4
file	sbin/newfs/Makefile		: 1.30
file	sbin/newfs_sysvbfs/Makefile	: 1.2
file	sbin/restore/Makefile		: 1.23
file	sbin/veriexecctl/Makefile	: 1.11
file	sys/lib/libsa/Makefile		: 1.59
file	sys/arch/evbarm/adi_brh/brh_machdep.c : 1.24
file	usr.bin/awk/Makefile		: 1.9
file	usr.bin/crontab/Makefile	: 1.24
file	usr.bin/ctags/Makefile		: 1.8
file	usr.bin/gzip/Makefile		: 1.10
file	usr.bin/ssh/sftp/Makefile	: 1.10
file	usr.bin/ssh/ssh/Makefile	: 1.25
file	usr.bin/vi/build/Makefile	: 1.26
file	usr.bin/telnet/Makefile		: 1.40
file	usr.bin/tn3270/tn3270/Makefile	: 1.36
file	usr.bin/tr/Makefile		: 1.4
file	usr.sbin/amd/amd/Makefile	: 1.27
file	usr.sbin/amd/amq/Makefile	: 1.14
file	usr.sbin/amd/libamu/Makefile	: 1.20
file	usr.sbin/amd/pawd/Makefile	: 1.5
file	usr.sbin/bind/Makefile.inc	: 1.22
file	usr.sbin/bind/libdns/Makefile	: 1.3
file	usr.sbin/bind/named/Makefile	: 1.17
file	usr.sbin/bootp/bootptest/Makefile : 1.2
file	usr.sbin/chrtbl/Makefile	: 1.6
file	usr.sbin/cron/Makefile		: 1.12
file	usr.sbin/dhcp/Makefile.inc	: 1.20
file	usr.sbin/dumplfs/Makefile	: 1.11
file	usr.sbin/hprop/Makefile		: 1.13
file	usr.sbin/installboot/Makefile	: 1.35
file	usr.sbin/ipf/ipftest/Makefile	: 1.32
file	usr.sbin/isdn/isdnd/Makefile	: 1.6
file	usr.sbin/isdn/isdnmonitor/Makefile : 1.3
file	usr.sbin/isdn/isdntel/Makefile	: 1.2
file	usr.sbin/isdn/isdntrace/Makefile : 126
file	usr.sbin/mopd/common/Makefile	: 1.10
file	usr.sbin/mopd/mopd/Makefile	: 1.9
file	usr.sbin/mopd/mopprobe/Makefile	: 1.7
file	usr.sbin/makefs/Makefile	: 1.17
file	usr.sbin/mscdlabel/Makefile	: 1.5
file	usr.sbin/pkg_install/add/Makefile : 1.7
file	usr.sbin/pkg_install/create/Makefile : 1.5
file	usr.sbin/pkg_install/lib/Makefile : 1.28
file	usr.sbin/ntp/ntpd/Makefile	: 1.10/1.11
file	usr.sbin/ntp/ntptime/Makefile	: 1.4/1.5
file	usr.sbin/pppd/Makefile.inc	: 1.3
file	usr.sbin/pppd/pppd/Makefile	: 1.38
file	usr.sbin/rarpd/Makefile		: 1.10
file	usr.sbin/rbootd/Makefile	: 1.10
file	usr.sbin/rpc.pcnfsd/Makefile	: 1.17
file	usr.sbin/rtadvd/Makefile	: 1.9
file	usr.sbin/tcpdump/Makefile	: 1.42
file	usr.sbin/wiconfig/Makefile	: 1.3
descr
	GCC 4.1 warns on pointer sign comparision/assignments and lots of
	code does not conform.  For now we use -Wno-pointer-sign and
	-fno-strict-aliasing.
kcah

hack	cross-building hack on Darwin
mdate	20 July 2008
who	agc
file	src/distrib/common/Makefile.mdset	: 1.33
descr
	Darwin has problems with getopt() when used in mdsetimage -v,
	due to the difference between BSD and libiberty() getopt
	implementations, more fully described in
	http://mail-index.netbsd.org/current-users/2008/06/27/msg003242.html
	and the subsequent thread.  For just now, we just have an ugly
	workaround not to call mdsetimage with the -v argument on Darwin
kcah

hack	avoid rebuilding asn1 libraries
mdate	03 August 2008
who	veego
file	src/crypto/dist/heimdal/lib/asn1/gen.c	: 1.10
file	src/lib/libasn1/Makefile	: 1.32
file	src/lib/libhdb/Makefile	: 1.23
file	src/lib/libgssapi/Makefile	: 1.20
file	src/lib/libhx509/Makefile	: 1.3
pr	9702 39185
descr
	asn1_compile does not check if generated header files do not have to
	be rebuild.
	Generate .hx files and copy it in the Makefiles if they changed.
kcah

hack	avoid gcc4 -O1 bug in loop optimize
cdate	29 November 2008
who	tsutsui
file	src/sbin/ifconfig/Makefile	: 1.39
pr	40036 40066
descr
	gcc -O1 seems to generate wrong code in loop optimize so that
	ifconfig lo0 inet6 doesn't return error even if a kernel
	doesn't have IPv6 support. (see the above PRs for details)
	For workaround, specify -fno-loop-optimize on m68000,
	which uses -O1 by default.
kcah

hack	MKPIE ldscript for /usr.sbin/crash
cdate	22 April 2010
who	christos
file	src/usr.sbin/crash/Makefile	: 1.5
file	src/usr.sbin/crash/ldscript.crash	: 1.1
pr	N/A
descr
	fixed in binutils-2.20.1. Linking with MKPIE=yes causes overlapping
	sections
kcah

port	vax

	hack	gcc4/vax ICE
	cdate	
	who	tsutsui
	file	sys/arch/vax/conf/Makefile.vax
	descr
		GCC4 on vax gets ICE on compiling sys/ddb/db_command.c.
		-fno-tree-ter prevents it so add it to COPTS.
	kcah

	hack	gcc4/vax compiler crash
	cdate	Fri Jun 30 22:39:12 PDT 2006
	who	mrg
	file	bin/csh/Makefile	: 1.27
	file	lib/i18n_module/UTF7/Makefile	: 1.2
	descr
		GCC4 on vax crashes.  -O0 stops it happening so far...
	kcah

	hack	gcc 2.95/vax doesn't like abort being used as function pointer
	cdate	Tue Dec 13 05:54:50 GMT 2005
	who	jmc
	file	lib/libc/rpc/svc_vc.c 1.15
	descr
		Provide a local definition for abort which doesn't include
		the noreturn attribute which trips up gcc 2.95 on vax.
	kcah
	
	hack	gcc 2.95/vax doesn't have stdbool.h and gettext needs it
	cdate	Mon May  9 12:16:22 CDT 2005
	who	jmc
	file	gnu/usr.bin/gettext/Makefile.inc.prog 1.5
		gnu/usr.bin/gettext/libgrep/Makefile 1.3
		gnu/usr.bin/gettext/libnlspr/Makefile 1.5
		gnu/usr.bin/gettext/libnlsut/Makefile 1.3   
	descr
		The latest gettext assumes a C99 environment or at least
		configure checks to work around this. As we don't use configure
		provide a stdbool.h for vax builds locally in directories from
		the template provided by the gettext code.
	kcah
	
	hack	gcc 2.95/vax cannot handle __builtin_ffs()
	cdate	Fri Aug 23 21:31:15 CEST 2002
	who	ragge
	file	sys/lib/libkern/libkern.h : 1.42
	descr
		__builtin_ffs() is ifdef'd away if __vax__. Matt Thomas has
		added this feature to GCC 3 so it can be removed when switching.
	kcah

	hack	gcc 2.95/vax libbz2
	mdate	27 Jun 2002
	who	thorpej
	file	lib/libbz2/Makefile
	descr
		libbz2 is mis-compiled with optimization with GCC 2.95.3
		on VAX.  -O0 works around this problem.
	kcah

	hack	vax Toolchain bug
	cdate	28 Mar 2003
	who	he
	file	sys/arch/vax/vax/intvec.S : 1.5
	descr
		Workaround for PR toolchain/20924.  The assembler apparently
		tries to range-check byte offsets when it doesn't have
		sufficient information to make that decision.
		Workaround uses `brw' instead of `brb' instruction.
	kcah

	hack	vax gcc 2.95.3 -Wuninitialized workarounds
	cdate	6 Nov 2003
	who	he
	file	sys/dev/bi/if_ni.c : 1.22
	file	sys/arch/vax/vax/ctu.c : 1.20
	descr
		Workaround for gcc 2.95.3 failing to detect that certain
		variables will be initialized; so that this code compiles
		with -Wuninitialized.  Should be reviewed and possibly
		reverted when gcc 3.3.2 is ready for vax.
	kcah

	hack	vax gcc 2.95.3 structure initialization
	cdat	13 May 2004
	who	cl
	file	sys/miscfs/kernfs/kernfs_vnops.c : 1.104
	descr
		Workaround for gcc 2.95.3 failing to initialize structures
		and/or unions inside structures using nested designators.
		Should be reverted when gcc >=3.3.3 is ready for vax.
	kcah

	hack	vax gcc 2.95.3 needs -I. to build nslexer.c
	cdat	6 Jun 2004
	who	mhitch
	file	lib/libc/arch/vax/Makefile.inc : 1.6
	descr
		It appears necessary to add -I. to CPPFLAGS when building
		nslesxer.c.  This may be caused by gcc 2.95.3 being used.
		Should be reverted when a newer gcc is ready for vax.
	kcah

	hack	vax gcc 2.95.3 doesn't understand "-std=c99"
	cdat	5 April 2005
	who	tron
	file	src/share/mk/bsd.sys.mk
	descr
		We cannot use "-std=c99" for compiler warning level 4 and above
		because gcc 2.95.3 doesn't support that option.
	kcah

	hack	declare boolean_t in two IPF user-mode programs
	cdate	Tue Mar  7 19:19:20 CET 2006
	who	he
	file	dist/ipf/ipsend/iptests.c : 1.8
		dist/ipf/ipsend/sock.c : 1.7
	descr
		The IPF user-mode programs ipsend and iptest first
		include <sys/types.h> without _KERNEL defined, and
		later include <sys/file.h> with _KERNEL defined.
		This causes a build failure when building for vax,
		since <sys/device.h> ends up being included without
		bollean_t being defined by <sys/types.h>.
		Build failure and further details documented in
		PR#32907.
	kcah

	hack	pcc 0.9.9 large string literals
	cdat	8 July 2008
	who	gmcgarry
	file	sys/conf/param.c : 1.58
	descr
		Workaround for pcc 0.9.9 not handling large string literals
		which causes kernels with 'options INCLUDE_CONFIG_FILE' to
		fail compilation.
		There is a proposal on the pcc mailing list to stuff config
		file in ELF section.
	kcah

	hack	xorg warnings
	cdat	30 July 2008
	who	mrg
	file	external/mit/xorg/lib/libSM/Makefile : 1.2
		external/mit/xorg/lib/libX11/Makefile.libx11 : 1.2
		external/mit/xorg/lib/libXext/Makefile : 1.2
		external/mit/xorg/lib/libXfont/Makefile : 1.2
	descr
		Disable several warnings or use -Wno-error across Xorg sources
		while we get them working
	kcah

	hack	32 bit time leftovers
	cdat	11 January 2009
	who	christos
	file	lib/libc/time/localtime.c : 1.41
		lib/libc/time/zic.c : 1.23
	descr
		The timezone compiled files still contain 32 bit time_t
		quantities. I did not want to version the files because
		the ``parser'' is too ugly for words. What needs to be
		done, is to rewrite the parser from scratch also to avoid
		potential core-dumps from parsing invalid files.
	kcah

	hack	32 bit time leftovers
	cdat	11 January 2009
	who	christos
	file	various
	descr
		Many filesystem on-disk formats have 32 bit times.
	kcah

port	arm

	hack	gcc-unsigned-compare
	cdate	09 Mar 2002
	mdate	18 Mar 2002
	who	bjh21
	file	dist/bind/lib/nameser/ns_parse.c : 1.3
	file	dist/dhcp/minires/ns_parse.c : 1.3
	file	dist/dhcp/omapip/result.c : 1.2
	file	dist/dhcp/server/failover.c : 1.3
	file	gnu/dist/toolchain/bfd/bfd.c : 1.2
	file	gnu/dist/toolchain/bfd/format.c : 1.2
	file	gnu/dist/toolchain/gdb/target.c : 1.2
	file	sys/kern/vfs_subr.c : 1.172
	descr	When checking that a potentially-unsigned enum is >= 0, assign
		it to an int first.  This is necessary to avoid "comparison is
		always true" warnings with -fshort-enums.  Casting to an int
		really should be enough, but turns out not to be.
	kcah


port	sh3

	hack	gcc4-sh3-bz2
	cdate	Sun May 21 03:34:57 UTC 2006
	mdate	Fri May 16 13:13:00 UTC 2008
	who	mrg, tsutsui
	file	lib/libbz2/Makefile	: 1.10
	descr
		The in-tree GCC 4.1-based compiler generated too-far
		pc-relative addresses.  Hack is to build with
		-fno-loop-optimize.
	kcah


port	m68000

	hack	gcc4-m68000
	cdate	Fri Feb  8 10:29:37 PST 2008
	mdate	Sun May  4 15:37:19 UTC 2008
	who	mrg, tsutsui
	file	rescue/Makefile	: 1.21
	file	sbin/dump_lfs/Makefile	: 1.9
	file	sbin/fsck_ffs/Makefile	: 1.35
	file	sbin/fsdb/Makefile	: 1.22
	file	share/mk/sys.mk	: 1.96
	file	usr.sbin/ndbootd/Makefile	: 1.5
	descr
		Several internal compiler errors with gcc -O1
		around 64bit integer arithmetic.
		This hack uses -O1 and adds some -fno-tree-foo options
		to avoid the problem.
		This might be related with GCC Bugzilla Bug 32424.
	kcah


port	sparc

	hack	avoid NULL pointer derefs in savefpstate IPIs and GCC 4.5.3
	cdate	Sun Aug 14 19:26:48 PDT 2011
	who	mrg
	file	sys/arch/sparc64/sparc/cpu.c : 1.234
	file	sys/arch/sparc64/sparc/cpuvar.h : 1.90
	file	sys/arch/sparc64/sparc/genassym.cf : 1.67
	file	sys/arch/sparc64/sparc/locore.s : 1.265
	descr
		Something is wrong with GCC 4.5.3 and the savefpstate IPI.
		Post newlock2 there was a bug where a lock was reduced from
		IPL_SCHED to IPL_VM (?) and occasionally savefpstate IPI
		would crash due to NULL IPI.  This was fixed by re-using the
		right IPL value.  However, GCC 4.5.3 build kernels have the
		same problems.  For now, the hack is re-instated.
	kcah


port	sparc64

	hack	disable optimzations for uvm_bio.c on 32 bit kernels
	cdate	Sun Mar 21 14:14:04 MET 2004
	who	martin
	file	sys/arch/sparc64/conf/Makefile.sparc64 : 1.53-1.54
	file	sys/arch/sparc64/conf/files.sparc64 : 1.93
	descr
		The sparc compiler miscompiles uvm_bio.c when using
		any optimization. This results in ubc_release panics.
	kcah


port	mips

	hack	mips-shared-linker-load-address
	cdate	Fri Oct  7 08:33:10 UTC 2005
	who	simonb
	file	src/sys/kern/exec_elf32.c : 1.107
	descr
		With COMPAT_16 or previous enabled (which enables
		ELF_INTERP_NON_RELOCATABLE) a recent ld.elf_so will
		load and run at address 0.  The check to fix this in
		rev 1.107 only checks the first psection of the ELF
		executable, which may not be loadable.  A more correct
		fix is to check the first loadable psection instead of
		just the first psection.
	kcah

	hack	mips-duplicate-ras-end-label
	cdate	Sat Sep  2 23:29:42 2006
	who	martin
	file	src/regress/sys/kern/ras/ras3/Makefile : 1.3
	descr
		Add -fno-reorder-blocks to CFLAGS to avoid duplicate
		labels by duplicated __asm output from RAS_END()
		macro.
	kcah

	hack	mips-mcount-assembler-warning
	cdate	Tue Jul 29 14:16:52 UTC 2008
	who	lukem
	file	src/lib/libc/gmon/Makefile.inc : 1.8
	descr
		Workaround for PR port-mips/39192.
		common/lib/libc/gmon/mcount.c generates a (fatal)
		assembler warning on MIPS:
			Warning: No .cprestore pseudo-op used in PIC code
		Add COPTS.count.c+=-Wa,--no-warn to avoid -Wa,--fatal-warnings
	kcah

port	i386

	hack	use volatile intermediate variable to enforce rounding
	cdate	Tue Aug  1 22:15:55 MEST 2006
	who	drochner
	file	src/lib/libm/src/lrintf.c : 1.4
	file	src/lib/libm/src/s_rintf.c : 1.8
	descr
		gcc-4 does subsequent operations on "float" values within
		the i387 FPU without rounding the intermediate results
	kcah

port	powerpc

	hack	avoid using __builtin_return_address(0) because it fails in
		Xorg's module loader
	cdate	Sat Sep 27 03:52:05 UTC 2008
	who	macallan
	file	src/libexec/ld.elf_so/rtld.c : 1.121
	descr
		workaround for PR port-macppc/37812
	kcah

	hack	define TARGET_SECURE_PLT and HAVE_AS_TLS because when
		building the native compiler via build.sh those don't defined
		properly.
	cdate	Sat Mar 12 08:00:00 UTC 2011
	who	matt
	file	src/gnu/dist/gcc4/gcc/config/rs6000/netbsd.h
	descr
		see above
	kcah